The only way a case for item not as described can be closed by eBay or the seller is if you opened the case too late, that is, you opened it after 30 days from the last estimated date for delivery has lapsed.
Or, on opening the case the seller had 3 days to refund or send a prepaid label for its return. If they did not you Must escalate.
If you did not escalate the case times out and closes after 30 days, eBay think because of inactivity, the matter has been resolved between buyer and seller.
You cannot open another case for this item with eBay, but can try and turn to your payment provider for help with your refund now.
@trickymurphson